Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "model error" wg kryterium: Temat

  Lista filtrów

Dostawca treści

Wyrównaj
Wyświetlanie 1-15 z 97
Tytuł:
Handling ambient temperature changes in correlative thermal error compensation
Autorzy:
Naumann, Christian
Geist, Alexander
Putz, Matthias
Powiązania:
https://bibliotekanauki.pl/articles/28407326.pdf
Data publikacji:
2023
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
machine tool
thermal error
correlative compensation model
ambient effect
ETVE
environmental temperature variation error
Opis:
Thermal errors are one of the leading causes for positioning inaccuracies in modern machine tools. These errors are caused by various internal and external heat sources and sinks, which shape the machine tool’s temperature field and thus its deformation. Model based thermal error prediction and compensation is one way to reduce these inaccuracies. A new composite correlative model for the compensation of both internal and external thermal effects is presented. The composite model comprises a submodel for slow long- and medium-term ambient changes, one for short-term ambient changes and one for all internal thermal influences. A number of model assumptions are made to allow for this separation of thermal effects. The model was trained using a large number of FE simulations and validated online in a five-axis machine tool with measurements in a climate chamber. Despite the limitations, the compensation model achieved good predictions of the thermal error for both normal ambient conditions (21°C) and extreme ambient conditions (35°C).
Źródło:
Journal of Machine Engineering; 2023, 23, 4; 43--63
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance analysis of MPPM FSO transmission over Gamma–Chi-square strong atmospheric turbulence
Autorzy:
Todorovic, Jelena
Spalevic, Petar
Panic, Stefan
Abdullah, Majid Hamid
Pantelic, Ivan
Powiązania:
https://bibliotekanauki.pl/articles/2202766.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
FSO
free space optics
ABER
average bit error rate
MPPM
multi-pulse pulse-position
novel Gamma-Chi-square distribution
channel model
strong atmospheric turbulence
Opis:
In this paper, performance analysis of free space optical (FSO) system operating in conditions of strong atmospheric turbulence over Gamma–Chi-square turbulence model, has been carried out. We have observed reception over multi-pulse pulse-position (MPPM) modulation format for the case of strong atmospheric turbulence conditions modeled with Gamma–Chi-square turbulence model and have compared it with turbulence modeling distributions such are: Gamma–Gamma distribution, K-distribution, negative exponential distribution, log–normal distribution. First, we have provided closed-form analytical expressions for average bit error rate (ABER) at the reception for each observed case and then based on them, we have obtained numerical and Monte Carlo simulation results in order to observe turbulence level impact on system performance.
Źródło:
Optica Applicata; 2023, 53, 1; 111--126
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polish Finishers from Danish Piglets: Uncontrolled Transformation of Pig Industry in Poland
Polskie tuczniki z duńskich prosiąt – niekontrolowana transformacja polskiego sektora trzody chlewnej
Autorzy:
Olipra, Jakub
Powiązania:
https://bibliotekanauki.pl/articles/43195744.pdf
Data publikacji:
2023-06-28
Wydawca:
Instytut Ekonomiki Rolnictwa i Gospodarki Żywnościowej - Państwowy Instytut Badawczy
Tematy:
rynki rolne
sektor trzody chlewnej
bezpieczeństwo żywnościowe
specjalizacja rynkowa
VECM
ceny
agricultural markets
pig industry
food security
market specialization
vector error correction model
prices
Opis:
Jeszcze 20 lat temu Polska była samowystarczalna w produkcji świń, będąc jednym z kluczowych graczy na europejskim rynku trzody chlewnej. Od tego czasu obserwuje się rosnącą specjalizację Polski w zakresie tuczu świń i przetwórstwa mięsa, przy jednoczesnym spadku krajowej produkcji prosiąt. W konsekwencji Polska utraciła samowystarczalność w produkcji świń i stała się silnie uzależniona od importu prosiąt, głównie z Danii. Celem niniejszego opracowania jest podsumowanie ewolucji polskiego sektora trzody chlewnej oraz określenie głównych determinant polskiego importu prosiąt z Danii. Wyniki oszacowań przy użyciu modelu VECM wskazują, że wielkość polskiego importu prosiąt z Danii może być wyjaśniona przez stopień specjalizacji Polski w zakresie tuczu świń, fazę cyklu świńskiego oraz konkurencyjność polskiej wieprzowiny. Wyniki mogą być pomocne w zrozumieniu ewolucji polskiego sektora trzody chlewnej i jego rosnącego uzależnienia od importu prosiąt.
Only 20 years ago, Poland was self-sufficient in pig production, being one of the key players in the Euro- pean pig market. Since then a growing specialization of Poland in pig finishing and meat processing has been observed, while the domestic production of piglets has declined. As a consequence, Poland has lost its self-sufficiency in pig production and become strongly dependent on imports of piglets, mainly from Denmark. The aim of this paper is to summarize the evolution of the Polish pig industry and specify the main determinants of the Polish imports of Danish piglets. The results of the estimates using the vector error correction model (VECM) show that the volume of the Polish imports of piglets from Denmark may be explained by a degree of specialization of Poland in pig finishing, the phase of pig cycle, and the competitiveness of Polish pork. The results may be helpful in understanding the evolution of the Polish pig industry and its growing dependence on imports of piglets.
Źródło:
Zagadnienia Ekonomiki Rolnej; 2023, 375, 2; 1-21
0044-1600
2392-3458
Pojawia się w:
Zagadnienia Ekonomiki Rolnej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variable antennas positions solution to reduce pointing errors due to wind speed and temperature coupled effects during free space optical link using matrix Rician pointing error model
Autorzy:
Teuma Mbezi, Michel
Eke, Samuel
Som, Idelette Hermine Judith
Mouangue, Ruben Martin
Powiązania:
https://bibliotekanauki.pl/articles/27310098.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
atmospheric turbulence
pointing error
free space optical transmission
Rician pointing error model
Opis:
Pointing errors (PE) during free space optical (FSO) transmission can be caused by laser beam wander due to thermal and wind dynamic instability. The aim of this work is to study the coupled effects of temperature and wind speed on PE using matrix Rician pointing error (MRPE) model; then show how variable antennas height can reduce PE due to wind speed and temperature coupled effects. To achieve this purposes, average PE expression was established using MRPE model. Then considering a Gaussian beam wave and Monin–Obukhov similarity functions for the structure parameters of temperature, explicit relationship was established between average PE, temperature and wind speed. It comes out of this study that under dynamic turbulence, one can appropriately modify temperature to reduce PE due to dynamic instability and reciprocally. Depending on turbulence large cells or frozen turbulence eddies distribution, PE can be reduced by appropriately modified antennas height or the distance between transmitter and receiver. That is why this work suggests to install variable or dynamic antennas (rather than fixed ones) which could intelligently modify its positions according to laser beam wander created by atmospheric turbulence.
Źródło:
Optica Applicata; 2023, 53, 3; 393--406
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of the publicly available digital terrain model provided by the head office of geodesy and cartography with GNSS satellite measurement
Porównanie powszechnie dostępnego Numerycznego Modelu Terenu udostępnianego przez Główny Urząd Geodezji i Kartografii z pomiarem satelitarnym GNSS
Autorzy:
Zygmunt, Mariusz
Boduszek, Wojciech
Powiązania:
https://bibliotekanauki.pl/articles/2124659.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Rolniczy im. Hugona Kołłątaja w Krakowie
Tematy:
digital terrain model
point cloud
DTM error
GNSS
NMT
chmura punktów
błąd NMT
model numeryczny terenu
Opis:
Due to the ever-better accessibility of the digital terrain model (DTM), it is enjoying growing popularity as a source of information about the surrounding world. It became even more approachable when DTM data covering the whole of Poland was made available free of charge on the Geoportal website. The GRID with a resolution of 1 meter per 1 meter covers virtually the entire country. The data on the Geoportal does not only refer to the measurements processed into a grid of squares, but also includes measurement data. They can be accessed through a systematic division into section sheets in the 1992 system. The paper presents research on assessing the accuracy of these publicly available data, compared to measurements obtained with the GNSS observations. The analysis involved data directly from the measurement device, not yet processed into a grid of squares. As part of the research, the height of 3 objects was compared. It was decided to measure the terrain profiles. To get as close as possible to the source data provided at the Geoportal website, the selected points of profiles previously identified in the point cloud were measured. This approach freed the final results from the need for height interpolation for the data selected for analysis. As result, the potential source of errors in such an approach was eliminated. Although during a classical profile measurement with this technology the selection of points would certainly be different, for research purposes this approach seems optimal. For this reason, in addition to the expected deviations resulting from the height differences of the tested points, deviations from the data from the point cloud of the XY coordinates, related to the adopted technology, are also presented.
Numeryczny model terenu (NMT) jako źródło informacji o otaczającym nas świecie wraz z dostępem do niego staje się coraz bardziej powszechny. Korzystanie z niego stało się jeszcze prostsze w momencie udostępnienia nieodpłatnie danych NMT obejmujących całą Polskę na stronach Geoportalu. Siatka GRID o rozdzielczości 1 metr na 1 metr pokrywa praktycznie cały kraj. Dane zawarte na stronach Geoportalu nie dotyczą tylko przetworzonych pomiarów do siatki kwadratów, ale zawierają także dane pomiarowe. Dostęp do nich jest możliwy poprzez usystematyzowany podział na arkusze sekcyjne w układzie 1992. Artykuł przedstawia prace badawcze polegające na ocenie dokładności tych ogólnodostępnych danych w porównaniu z pomiarem uzyskanym za pomocą obserwacji GNSS. Analizie poddano dane pochodzące bezpośrednio z pomiaru, nie przetworzone do siatki kwadratów. W ramach badań przeprowadzono porównanie wysokości dla 3 obiektów. Zdecydowano się na pomiar profili terenu. Aby podczas badań maksymalnie zbliżyć się do danych źródłowych udostępnionych na stronach Geoportalu, zdecydowano się na pomiar wybranych punktów profili zidentyfikowanych wcześniej na chmurze punktów. Tego typu podejście uwolniło wyniki końcowe z potrzeby interpolacji wysokości dla wybranych do analizy danych. Skutkowało to wyeliminowaniem potencjalnego źródła błędów wynikających z takiego podejścia. Co prawda podczas klasycznego pomiaru profili tą technologią, wybór punktów byłby z pewnością inny, jednak dla celów badawczych takie podejście wydaje się optymalne. Z tego powodu oprócz oczekiwanych odchyłek wynikających z różnic wysokości dla badanych punktów, przedstawiono także odchyłki względem danych pochodzących z chmury punktów dla współrzędnych XY, wynikające z przyjętej technologii.
Źródło:
Geomatics, Landmanagement and Landscape; 2022, 1; 103--116
2300-1496
Pojawia się w:
Geomatics, Landmanagement and Landscape
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of Turboshaft Engine Adaptive Dynamic Model: Analysis of Estimation Errors
Autorzy:
Yepifanov, Sergiy
Bondarenko, Oleksiy
Powiązania:
https://bibliotekanauki.pl/articles/36807197.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
turbine engine
turboshaft
gas generator
dynamic model
engine time constant
identification
estimation error
design of experiment
Opis:
One of the most perspective directions of aircraft engine development is related to implementing adaptive automatic electronic control systems (ACS). The significant elements of these systems are algorithms of matching of mathematical models to actual performances of the engine. These adaptive models are used directly in control algorithms and are a combination of static and dynamic sub-models. This work considers the dynamic sub-models formation using the Least Square method (LSM) on a base of the engine parameters that are measured in-flight. While implementing this function in the (ACS), the problem of checking the sufficiency of the used information for ensuring the required precision of the model arises. We must do this checking a priori (to determine a set of operation modes, the shape of the engine test impact and volume of recorded information) and a posteriori. Equations of the engine models are considered. Relations are derived that determine the precision of parameters of these models’ estimation depending on the precision of measurement, the composition of the engine power ratings, and durability of observations, at a stepwise change of fuel flow. We present these relations in non-dimensional coordinates that make them universal and ready for application to any turboshaft engine.
Źródło:
Transactions on Aerospace Research; 2022, 4 (269); 59-71
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Practical aspects of the use of the sluice gate discharge equations to estimate the volumetric flow rate in the irrigation channels
Autorzy:
Kubrak, Elżbieta
Kubrak, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/2174345.pdf
Data publikacji:
2022
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
discharge coefficient
discharge calculation error
irrigation channel
laboratory model investigations
submerged sluice gate flow
volumetric flow rate
Opis:
The article presents the experimental results of the calibration of the typical check structure with sluice gates installed in a trapezoidal irrigation channel. Hydraulic experiments on sluice gate discharge capacity were performed on a model made in a 1:2 scale. It has been explained how the method of measuring the downstream water depth below the sluice gate in the check structures installed in a trapezoidal irrigation channels affects the measured depth values. On the basis of hydraulic measurements, regression relationships were developed for the discharge coefficients for submerged outflow through the sluice gate in two types of sluice gates installed in irrigation channels. The formulas allow to calculate the volumetric flow rate below the submerged sluice gate after determining the water depth upstream and below the sluice gate and the gate opening height. The differences in volumetric flow rates calculated from regression relationships and measured values do not exceed 10%, which confirms their practical suitability for calculating the discharge through a sluice gate mounted in a trapezoidal channel. The values of the discharge coefficients determined in the channels with rectangular cross-sections are not useful for the discharge coefficients of sluice gates check structures installed in trapezoidal channels. Nomograms and relationships for discharge coefficients of the analysed sluice gate were developed.
Źródło:
Journal of Water and Land Development; 2022, 55; 129--137
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A fault tree-based approach for aviation risk analysis considering mental workload overload
Autorzy:
Che, Haiyang
Zeng, Shengkui
You, Qidong
Song, Yueheng
Guo, Jianbin
Powiązania:
https://bibliotekanauki.pl/articles/2038044.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
risk analysis
human error
mental workload overload
multiple resources model
fault tree analysis
Opis:
Many lives and aircrafts have been lost due to human errors associated with mental workload overload (MWLOL). Human errors are successfully considered in existing Fault Tree Analysis (FTA) methods. However, MWLOL is considered through Performance Shaping Factors indirectly and its information is hidden in FT construction, which is not conducive to analyze the root causes of human errors and risks. To overcome this difficulty, we develop a risk analysis method where Multiple Resources Model (MRM) is incorporated into FTA methods. MRM analyzes mental workload by estimating the resources used during performing concurrent tasks, probably including abnormal situation handling tasks introduced by basic events in FT. Such basic events may cause MWLOL and then trigger corresponding human error events. A MWLOL gate is proposed to describe MWLOL explicitly and add these new relationships to traditional FT. This new method extends previous FTA methods and provides a more in-depth risk analysis. An accident, a helicopter crash in Maryland, is analyzed by the proposed method.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 4; 646-658
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new predictive filter for nonlinear alignment model of stationary MEMS inertial sensors
Autorzy:
Alhassan, Hassan Majed
Ghahremani, Nemat Allah
Powiązania:
https://bibliotekanauki.pl/articles/2052163.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
predictive filter
nonlinear alignment
model error
optimization
MEMS inertial sensors
Opis:
This paper proposes a new approach called the Predictive Kalman Filter (PKF) which predicts and compensates model errors of inertial sensors to improve the accuracy of static alignment without the use of external assistance. The uncertain model error is the main problem in the field as the Micro Electro Mechanical System (MEMS) inertial sensors have bias which change over time, and these errors are not all observable. The proposed filter determines an optimal equivalent model error by minimizing a quadratic penalty function without augmenting the system state space. The optimization procedure enables the filter to decrease both model uncertainty and external disturbances. The paper first presents the complete formulation of the proposed filter. Then, a nonlinear alignment model with a large misalignment angle is considered. Experimental results demonstrate that the new method improves the accuracy and rapidness of the alignment process as the convergence time is reduced from 550 s to 50 s, and the azimuth misalignment angle correctness is decreased from 52′′ ± 47′′ to 4′′ ± 0.02′′.
Źródło:
Metrology and Measurement Systems; 2021, 28, 4; 673-691
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of climate variability on yield of maize and yam in Cross River State, Nigeria: An autoregressive distributed lag bound approach
Autorzy:
Edet, E. O.
Udoe, P. O.
Isong, I. A.
Abang, S. O.
Ovbiroro, F. O.
Powiązania:
https://bibliotekanauki.pl/articles/1031443.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Sustainable development
error correction model
food security
yield
Opis:
The study examined the impact of climate variability on yield of maize and yam in Cross River State, Nigeria. The specific objectives of the study were to determine the long-run and short-run impact of climate variability factors on yields of maize and yam. Data were sourced from the Nigerian Meteorological Agency (NiMeT) and Cross River State Ministry of Agriculture spanning from 1990-2016. Data obtained were analyzed using inferential statistics. Precisely, the model was estimated by the Ordinary Least Squares (OLS) multiple regression technique, which is within the Autoregressive Distributed Lag Bound approach and error correction testing framework. Both model-1 (maize yield) and model-2 (yam yield) passed through the conditions of the diagnostics and stability test. The study revealed that climate variables had a significant impact on maize yield both in the long and short-run. Based on the findings, it was concluded that proactive measures should be put in place to aid crop farmers adapt to the prevailing and looming threats of climate variability for the purpose of attaining the State’s food security balance sheet. To sustain this drive, an institutional and infrastructural support system is advocated in order to meet one of the goals of sustainable development agenda of the United Nations. Policy recommendations on how to cushion the impact of climate variability on the prescribed crops have been appropriately cited.
Źródło:
World News of Natural Sciences; 2021, 36; 60-74
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of international trade on employment in orange industry of South Africa
Autorzy:
Molepo, Nkoti Solly
Belete, Abenet
Hlongwane, Jan
Powiązania:
https://bibliotekanauki.pl/articles/1886408.pdf
Data publikacji:
2021-07-04
Wydawca:
Uniwersytet Przyrodniczy w Poznaniu. Wydawnictwo Uczelniane
Tematy:
South African orange industry
employment, wages
international trade
Johansen cointegration
vector error
correction model
Opis:
The purpose of the study is to analyse the long-run and short-run dynamic relations amongst total employment (lnEMPGt), export output (EXPOt) and import output (IMPOt) from 1990 to 2018, by applying a time-series analysis. The study adopts the secondary data for total employment from the Citrus Growers Association of South Africa, while both export and import output were sourced from the Global Trade Atlas. The multivariate cointegration approach is adopted in the study to identify any causal relationships amongst the concerned variables. The chosen optimum lag selection criterion was the Akaike Information Criterion (AIC) due to its association dependence on the log-likelihood ratio. The third lag was selected for the entire analysis. The results from the cointegration test and the Vector Error Correction Model (VECM) suggest a positive long-run effect between total employment and export output, while import output is negatively associated with total employment. The adjustment term of lnEMPGt, EXPOt and IMPOt suggests that the previous year’s errors are corrected for the current year at a convergence speed of 0.002, 1.11 and 25.37 percentage points, respectively. The results of the Granger causality test show that there are bidirectional causality effects between export output and total employment in the long run, while there are no causality effects between import output and total employment. The overall conclusion is that export outputs positively impact employment, while import outputs impact it negatively in the South African orange industry.
Źródło:
Journal of Agribusiness and Rural Development; 2021, 60, 2; 193-201
1899-5241
Pojawia się w:
Journal of Agribusiness and Rural Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the settlement prediction in soft soil by Richards Model: based on a linear least squares-iteration method
Autorzy:
Nadeem, Muhammad
Akbar, Muhammad
Huali, Pan
Xiaoqing, Li
Guoqiang, Ou
Amin, Azka
Powiązania:
https://bibliotekanauki.pl/articles/1852538.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metoda iteracji liniowej
metoda najmniejszych kwadratów
prognoza
grunt słaby
podłoże gruntowe
błąd porównawczy
osiadanie gruntu
model obliczeniowy
linear iterative method
least square method
prediction
soft soil
comparative error
settlement
calculation model
Opis:
Prediction of soft soil sub-grades settlement has been a big challenge for geotechnical engineers that are responsible for the design of roadbed embankment. The characteristics of low strength, poor permeability, high water contents, and high compressibility are dominant in soft soils, which result in a huge settlement in the case of long-term loading. The settlement prediction in soft soil subgrades of Jiehui Expressway A1, Guangdong, China, is the focus of this study. For this purpose, the necessary data of settlement is collected throughout the project execution. The numerical analysis is conducted by using the Richards model based on Linear Least Squares Iteration (LLS-I) method to calculate and predict the expected settlement. The traditional settlement prediction methods, including the hyperbolic method, exponential curve method, and pearl curve method, are applied on field settlement data of soft soil subgrades of Jiehui Expressway A1. The results show that the Richards model based on Linear Least Squares Iteration (LLS-I) method has high precision, and it has proven to be a better option for settlement prediction of soft soil sub-grades. The model analysis indicates that the mean absolute percentage error (MAPE) can be minimized as compared to other soft soil sub-grades settlement prediction methods. Hence, Richards's model-based LLS-I method has a capability for simulation and settlement prediction of soft soil subgrades.
Źródło:
Archives of Civil Engineering; 2021, 67, 2; 491-506
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long-term relationship estimation and coupling/decoupling analysis between motorway traffic and Gross Value Added. Specification of an ARDL cointegration approach and application to the Italian case study
Autorzy:
Pampigna, Andrea
Mauro, Raffaele
Powiązania:
https://bibliotekanauki.pl/articles/2067397.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
toll roads
motorway
traffic
cointegration
transport studies
error-correction model
Italian case study
drogi płatne
ruch na autostradzie
kointegracja
badania transportowe
model korekcji błędów
studium przypadku włoskie
Opis:
As transportation is an activity derived from spatial complementarities between a certain supply at an origin and a certain demand at a destination, according to a general axiom it seems that economic activities entail transport demand. In this perspective, an essential analysis deals with the quantification of the relationships between transport demand and certain socioeconomic variables. Elasticity is a concept widely used in transport economics as a measure of the responsiveness of transport demand concerning different factors represented as independent variables in an econometric model and coupling/decoupling concepts have been proposed in literature. This paper deals with the estimation of elasticities of motorway traffic demand based on Gross Value Added (GVA), and the consequent investigation of coupling/decoupling situation. The analysis is based on the application of an Autoregressive-Distributed Lag (ARDL) cointegration model with the F-bound test and of the related Error Correction model. Starting from the general ARDL model and the methodology for the verification of its robustness, the same model is applied to the Italian toll road network. The time series of GVA for goods and services and the overall length of the toll network from 1995 to 2019 are considered as explanatory variables of the total annual distance traveled by light and heavy vehicles. The various tests in the ARDL framework show a cointegration between the variables, under the fulfillment of all the diagnostic requirements. In this way, the long-term elasticities and the short-term adjustment dynamics are estimated separately for the goods and services components of GVA, and light and heavy vehicles. Starting from stable estimates of elasticities, the long-term coupling and decoupling effects between motorway traffic of light and heavy vehicles and the national production of goods and services can be shown. The paper, as well as providing an updated picture of the Italian situation, identifies a methodological framework that can be transferred to other contexts for a sector of great interest to investors, such as the motorway sector. All this can be useful to meet the needs of numerous stakeholders, who want to deepen the links between the economic cycle and traffic demand on toll motorways.
Źródło:
Archives of Transport; 2021, 60, 4; 39--56
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
Autorzy:
Rudnicki, Mariusz
Salamon, Roman
Marszal, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/2097703.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
numerical model
surface sea noise
quasi-spherical sea noise
DIFAR
bearing error
Opis:
Various types of passive sonar systems are used to detect submarines. These activities are complex and demanding. Therefore, computer simulations are most often used at the design stage of these systems. For this reason, it is also necessary to simulate the acoustic ambient noise of the sea. The article proposes a new numerical model of surface and quasi-spherical sea noise and presents its statistical parameters. The results of the application of the developed noise model to analyse the received signals of the DIFAR1 sonobuoy are also presented.
Źródło:
Archives of Acoustics; 2021, 46, 4; 591-604
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum inspiration to build a neural model based on the Day-Ahead Market of the Polish Power Exchange
Autorzy:
Ruciński, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/2052430.pdf
Data publikacji:
2021
Wydawca:
Uniwersytet Przyrodniczo-Humanistyczny w Siedlcach
Tematy:
Neural Modeling
day-ahead market
Polish power exchange
mean square error
determination index
quantum inspired neural model
Opis:
The article is an attempt of the methodological approach to the proposed quantum-inspired method of neural modeling of prices quoted on the Day-Ahead Market operating at TGE S.A. In the proposed quantum-inspired neural model it was assumed, inter alia, that it is composed of 12 parallel Perceptron ANNs with one hidden layer. Moreover, it was assumed that weights and biases as processing elements are described by density matrices, and the values flowing through the Artificial Neural Network of Signals are represented by qubits. Calculations checking the correctness of the adopted method and model were carried out with the use of linear algebra and vector-matrix calculus in MATLAB and Simulink environments. The obtained research results were compared to the results obtained from the neural model with the use of a comparative model.
Źródło:
Studia Informatica : systems and information technology; 2021, 1-2(25); 23-37
1731-2264
Pojawia się w:
Studia Informatica : systems and information technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 97

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies